POS0724 TRANSORBITAL ULTRASOUND IN NEWLY DIAGNOSED GIANT CELL ARTERITIS – A PROSPECTIVE STUDY
Authors: S. Petzinna, L. C. Burg, J. Terheyden, C. J. Bauer, C. Behning, P. Brossart, R. P. Finger, V. Schäfer
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Giant cell arteritis (GCA) is an immune-mediated, granulomatous vasculitis that primarily affects the elderly and results in local vascular changes of middle-sized and large arteries. A protracted diagnosis delaying high-dose corticosteroid therapy may result in permanent visual loss. Therefore, invasive and time-consuming biopsy of the superficial temporal artery has been replaced by high-resolution vascular ultrasound of the temporal and axillary artery to evaluate extracranial inflammation. Intracranial involvement of the ophthalmic vessels can be visualized by magnetic resonance imaging. Transorbital Ultrasound (TOS), as a simple and inexpensive diagnostic method, could be an option for assessing the optic nerve and the central retinal artery (CRA) and might improve diagnostic sensitivity in GCA, especially in anterior optic neuropathy (AION). <h3>Objectives</h3> The purpose of this study was to assess the utility of TOS in patients with untreated and newly diagnosed GCA. <h3>Methods</h3> Patients with new GCA diagnosed by a board-certified rheumatologist who also met the expanded ACR-EULAR classification criteria were enrolled in the study between October 1, 2018, and May 31, 2022. Each participant underwent TOS to assess the CRA and optic nerve diameter (OND). The eyes of the patients with GCA were categorized as eyes with or without visual impairment (VI), which was defined as transient or persistent visual field loss, diplopia, amaurosis, and blurred vision. Peak systolic velocity (PS), end diastolic velocity (ED), resistance index (RI) of the CRA and OND were recorded. <h3>Results</h3> A total of 54 GCA patients were prospectively enrolled in the study, 27 of whom had VI in at least one eye. To account for repeated measures within a patient, associations between TOS and VI were evaluated using linear mixed-effect models (LME). PS and ED values of the CRA were statistically significant lower in the eyes with GCA manifestation (ß=-1.93; p&lt;0.001 for PS; ß=-0.61; p=0.003 for ED). The RI of the CRA was statistically significant reduced in the eyes with GCA associated VI (ß=-0.04; p=0.007). OND was lower in the eyes with VI, too (ß=-0.36; p=0.06) (Table 1, Figure 1). <h3>Conclusion</h3> In TOS, eyes affected by VI exhibited significantly reduced PS, ED, and RI indicating an inflammatory process of the intracranial vessels leading to impaired blood flow to the optic nerve and contributing to ischemia-associated optic neuropathy. The shown decrease in OND is probably due to reduced blood flow and the resulting lessened vessel diameter and, in the case of a persistent depletion of blood flow, due to atrophic alterations of the optic nerve suggestive of irreversible damage. Therefore, VI in combination with decreased PS, ED, RI and OND may constitute a specific finding in the diagnosis of optic affection in GCA. Our study was the first to prospectively demonstrate the diagnostic value of TOS in untreated and new diagnosed GCA patients as a complementary diagnostic tool to assess GCA associated intracranial inflammation. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.